Aircraft typically include a plurality of flight control surfaces that, when controllably positioned, guide the movement of the aircraft from one destination to another. The number and type of flight control surfaces included in an aircraft may vary depending, for example, on whether the aircraft is a fixed-wing or rotary-wing aircraft. For example, most fixed-wing aircraft typically include primary flight control surfaces, such as a pair of elevators, a rudder, and a pair of ailerons, to control aircraft movement in the pitch, yaw, and roll axes. Aircraft movement of rotary-wing aircraft in the pitch, yaw, and roll axes is typically controlled by via movement of the rotating aircraft rotors, and may additionally be controlled via movement of one or more flight control surfaces.
The positions of the aircraft flight control surfaces and/or rotors are typically controlled via a flight control system. The flight control system, in response to position commands that originate from either the flight crew or an aircraft autopilot, moves the aircraft flight control surfaces and/or rotors to the commanded positions. In most instances, this movement is effected via actuators that are coupled to the flight control surfaces. Typically, the position commands that originate from the flight crew are supplied via one or more inceptors. For example, many fixed-wing aircraft include a plurality of inceptors, such as yokes or side sticks and rudder pedals, one set each for the pilot and for the co-pilot, and many rotary-wing aircraft include one or more of a cyclic, a collective, and rudder pedals. In many modern aircraft, including both fixed-wing aircraft and rotary-wing aircraft, electric motors are coupled to one or more of the inceptors to supply force feedback (or “haptic feedback”) to the user. These inceptors are generally referred to as active inceptors.
Depending on overall purpose and mission, some aircraft may be required to take off from environments that experience relatively low temperatures. Thus, many systems in these aircraft, including the above-mentioned active inceptors, may need to startup and run at these relatively low temperatures. In regard to the active inceptors, this may adversely impact the size of the motors that are used to supply the haptic feedback. In particular, relatively large motors may be needed due, at least in part, to the increased friction associated with lubricant properties, gear train tolerances, and bearing tolerances at the relatively low temperatures.
Hence, there is a need for active inceptors that may be implemented without overly large motors and still startup and operate in relatively low temperature environments. The present invention addresses at least this need.